Valve Done with the "Isolated Single-player Experience"?

There's another interesting quote posted on Kotaku from Geoff Keighley's recently released iPad app, The Final Hours of Portal 2: "Portal 2 will probably be Valve's last game with an isolated single-player experience," Keighley wrote, saying he heard this from both Gabe Newell and the company's project manager Erik Johnson. If you are trying to work out what this means, don't worry, as so is Valve, as Geoff adds: "What this all means is something Newell is still trying to figure out." They quote Keighley saying he considered this "curious," as do we, as Portal 2 joins Portal and the Half-Life series at the pinnacle of single-player gaming. It also casts another shadow on the forsaken Half-Life 2: Episode Three. Thanks nin.